The field of the present invention relates to archery bows. In particular, a dual cam archery bow is described herein wherein each power cable is simultaneously taken up at one end and let out at the other.
An exemplary prior-art dual-cam archery bow 10 is schematically illustrated in FIG. 1. Bow limbs 111a and 111b extend oppositely from handle 110. Cam assemblies 130a and 130b are rotatably mounted on limbs 111a and 111b, respectively. The cam assemblies are typically mirror images of one another. Draw cable 140 is secured at each end to the cam assemblies 130a and 130b and received in respective draw cable journals thereof. When the bow is drawn, the draw cable unwinds from the draw cable journals, thereby rotating the cam assemblies. A first power cable 145a is secured to the first cam assembly 130a and received in a power cable journal thereof, so that as the bow is drawn and the cam assembly 130a rotates, the power cable 145a is taken up. The other end of power cable 145a is secured to bow limb 111b, so that as the power cable 145a is taken up by the cam assembly 130a, the bow limbs are drawn toward one another. In an analogous fashion, power cable 145b is secured at one end to cam assembly 130b and received in a power cable journal thereof and is taken up when the bow is drawn, and is secured at its other end to bow limb 111a. The geometric profiles of the draw cable journals and the power cable journals determine the draw force versus draw distance for the bow. The cam assemblies are typically configured to yield a decrease in draw force near full draw (referred to as the “let-off”; typically expressed as a percentage decrease in draw force from the peak draw force). Relatively larger let-off is deemed desirable in the industry (greater than 65% reduction in draw force is deemed desirable, for example), as is increasing energy stored by the bow at full draw for a given amount of rotation of the cam assembly. For optimal bow performance, substantial synchronization of rotation of the cams is required, but often problematic to achieve in practice.
In prior art bows, the first end of each power cable is secured to a cam assembly, while the second end is secured directly to the other bow limb. (For this reason, such a power cable is sometimes referred to as an anchor cable.) Difficulties encountered in prior art bow designs may be at least partially mitigated by securing the second end of each power cable to the other cam assembly, as is disclosed hereinbelow.